Relay



July 2l, 1959 o. L. TAYLOR 2,896,051

y RELAY Filed March so, 195e 2 sheets-sheet 1 Owen L. Toylor.

ATTORNEY July 21, 1959 o. TAYLOR 2,896,051

RELAY Filed March so, i956 2 sheets-sheet 2 United States Patent O f'RELAY Owen L. Taylor, Easton, Conn., assignor to The Bryant ElectricCompany', Bridgeport, Conn., a corporation of Connecticut ApplicationMarch 30, 1956, Serial No. '575,035

Claims'. (Cl. Zim- 122) This invention relates generally to electricalrelays, and more particularly to a relay having two positions at whichit will remain after removal of operating force.

For certain applications, such as in the low voltage control ofresidential lighting, a number of relays are required of relativelysmall size, and in order to achieve maximum public acceptance theyshould be low in cost. For example, for residential lightingapplications, the relays should be small enough to be accommodated in astandard knockout hole of a standard electrical outlet box, and shouldbe susceptible of ready mounting therein. At the same time, the relaysmust be low in cost since a relay is needed for each electrical outlet.

One object of this invention, therefore, is to provide a novel,simplified type of relay having two positions to which it may beoperated, and having means to maintain it as each position after removalof the operating force.

Another object of this invention is to provide a novel type of thermaloperating means for a two position type of relay, which is capable ofoperating the relay to both of its positions.

Another object of this invention is to provide a novel operatingmechanism for a snap action type of switch contact.

Still another object of this invention is to provide a novel relay ofthe type described, with snap action contacts of the type having twostable positions, with electroresponsive means for operating thecontacts to each position.

A particular object of this invention is to provide a relay of the typedescribed having a novel casing structure adapted to be secured in aknockout hole of an outlet box by merely inserting a part of said casingtherein.

These and other objects of this invention will become more apparent fromconsideration of the following detailed description of preferredembodiments thereof, when taken in connection with the attacheddrawings, in which:

Figure 1 is a front elevational view of a relay constructed inaccordance with this invention with parts thereof being shown insection;

Fig. 2 is a side elevational view of the relay shown in Fig. lillustrating the relay contacts thereof;

Fig. 3 is a top view of the relay shown in Fig. l;

Fig. 4 is a transverse sectional view of the relay shown in Figs. l to 3taken substantially on the line IV-IV of Fig. l;

Fig. 5 is a partial sectional view of the lower supporting member for arelay similar to that shown in Figs. l to 4, but illustrating a modifiedtype of support for the relay operating member;

Fig. 6 is a sectional view of a relay similar to that shown in Figs. lto 4 and an outlet box, but with the relay being greatly reduced in sizeand embodying a modified form of supporting means for the parts of therelay, and including a casing for the relay; and

Fig. 7 is a schematic illustration of a circuit showing one way in whicha relay constructed in accordance with this invention may be utilized.

2,896,051 Patented July 21, 1959 While a relay may be constructed inaccordance with this invention in many different forms, the illustrativeembodiments of the invention shown on the drawings and hereinafterparticularly described, disclose particular forms of the invention whichhave been evolved for a particular application. Referring first to theform of the invention illustrated in Figs. 1 to 4, a supporting base isprovided for the parts of the relay comprising this invention whichincludes a plate portion 2, and a laterally projecting ledge portion 4,which may be formed integral with the plate portion 2, or separatelytherefrom, and secured thereto in any desired manner. The supportingbase comprising the two portions 2 and 4 should be of an electricalinsulating material, such as fiber or a molded insulating material.

The relay contacts are supported on the plate portionv 2 of thesupporting base, with one contact being supported on an angular terminalmember 6, one leg of which is secured to the plate portion 2 of the baseby a securing screw 8 which passes through an opening in the base and isthreaded into a threaded opening in the terminal 6. Therterminal 6 isprovided with a terminal screw 10 for the purpose of securing anelectrical conductor thereto, and the leg of the terminal 6 whichprojects laterally from the plate portion 2 has a stationary contact 12secured thereon by any suitable means, such as by welding or the like.The contact 12 is preferably of an arc re sistant electrical conductingmaterial, such as silver or a silver alloy.

The movable contact of the relay is supported on an angularly shapedterminal 14 having one leg secured to the plate portion 2 of the base bya fastening screw 16 in substantially the same manner as terminal 6, andthis same leg is also provided with a terminal screw 18, similar to theterminal screw 10 for the terminal 6. A contact blade 20 is adapted tobe mounted on the other leg of the terminal 14 by means of a clampingplate 24, and rivets 22 which pass through this leg of the terminal 14,and through the switch blade 20 and the clamping plate 24. The switchblade 20 is preferably of a resilient electrical conducting material,such as a copper alloy, and is formed so as to be operable to open andclose the relay contacts with a snap action. For this purpose the switchblade 20 is provided with a generally H-shaped opening 26 (Fig. 3) toform inwardly extending compression legs 28 and 30. The movable contact32 is mounted on the switch blade 20 adjacent the free end thereof. Thecontact 32 may be mounted on the switch blade 20 in the same manner thatcontact 12 is mounted on terminal 6, and may be of the same material.

A generally U-shaped actuating spring 34 is provided for causing theswitch blade to open and close the contacts of the relay with a snapaction, and this spring may be of any desired resilient material, such,for example, as spring steel. The outer ends of the legs of theactuating spring 34 are curved inwardly and then outwardly as at 36, andare assembled with the switch blade by stressing the legs of theactuating spring 34 towards each other so that the bent portions 36 canhave their outer surfaces engaged by the inner ends of thecompressionlegs 28 and 30, respectively, of the switch blade. The arrangement issuch that when the actuating spring 34 engages the compression legs 28and 30 of the switch blade 20, the actuating spring is under stress andthus exerts a compressive stress on the compression legs 28 and 3Q. Inorder to define the open circuit position of the relay contacts, anangularly shaped stop member 38 has one leg thereof secured to the plateportion 2 of the base, as by a securing screw 40 which extends throughthe base and is threaded into a threaded opening in this leg of the stopmember 38. The other leg of the stop manner about its points ofengagement with the compression legs 28 and 3i), to one side or theother of a central position where the compression legs 2S and 30 are inalignment. Thus, as viewed in Fig. l, the actuating spring 34 has movedin a counterclockwise direction from such a central position so that thecompression leg 28 extends beneath the main body of switch blade 20, andthe inner end of the compression leg 30 extends above the main body ofthe switch blade 20. This means that the line of force of the actuatingspring 34 is in a direction to move the free end of the switch blade 26upwardly to cause engagement of the movable contact 32 with thestationary contact 12. This is a stable position of the relay contactsso long as the actuating spring 34 is not permitted to move so'far in acounterclockwise direction that all stress in the spring is relieved.Now by simply moving the actuating spring 34 in a generally pivotalmanner in a clockwise direction, it will be observed that the line ofaction of the free ends of the actuating spring 34 will move over thecentral position where the compression legs 28 and 30 are in alignment,to a position where the line of action of this spring extends downwardlytoward the outer end of the switch blade 20 to cause the movable contact32 to suddenly move away from the stationary contact 12 and intoengagement with the stop member 38 with a snap action, which defines theopen circuit position of the relay contacts. This is also a stableposition of the contacts so long as the actuating spring 34 is notpermitted to go so far in a clockwise direction as would permit reliefof all stress in the actuating spring 34. Obviously, movement of theactuating spring in the reverse direction will result in the line ofaction of the actuating spring moving overcenter in the oppositedirection to close the contacts with a snap action.

In order to move the actuating spring 34 in opposite clockwise andcounterclockwise directions to operate the relay contacts, there isprovided an elongated operating plate 42 which is made of an insulatingmaterial, such as ber or a molded insulating material. The operatingplate 42 is provided with a central operating projection 43 at its upperend for engaging in a relatively large opening 44 in the bight portionof the operating spring 34. The lower edge of the operating plate 42 isprovided with an inwardly extending notch 46 substantially centrallythereof, which has a relatively small spring locating projection 4S atthe base of this notch. The notch 46 in the operating plate 42 providesspaced supporting legs 50 at the lower end of the operating plate 42which are adapted to be loosely received in a groove S2 formedtransversely of the ledge portion 4 of the supporting base. An opening56 is provided in the ledge portion 4 of the supporting base whichintersects the groove 52 in substantial alignment with the notch 46 inthe lower edge of the operating plate 42 when the plate is mounted inthe groove 52. A coil compression spring 54 is adapted to have its upperend received over the projections 48 in the notch 46 of the operatingplate 42, and its lower end received in the opening 56 in the ledgeportion 4 of the base, where it reacts against the inner end of anadjustable screw 5S threadedly engaged in the opening 56.

The operating plate 42 and its biasingl spring 54 are restrained byexpansible wires 60 and 62 at opposite sides of the operating plate 42,respectively. These wires 60 and 62 are of a relatively high resistanceelectrical conducting material, having, for example, a resistance ofseveral hundred ohms, and a suitable material may be a nickel-chromiumalloy, formed into a wire Vhaving a diameter of about 3 mils, butcapable of continuously carrying current in the control circuit to whichthese wires may be connected. The expansible wires 60 and 62 eachconnect the upper end of the operating plate 42 and a part rigid withthe base, as will be described. Each of the wires 60 and 62 is anchoredtoI identically formed spaced terminal strips 64. There are four of theterminal strips 64 mounted on the ledge portion 4 of the base, with twolocated at each side of the operating plate 42, and with each terminalstrip being secured to the ledge portion 4 of the base with a strip ofinsulating material 66 interposed between the terminal strips 64 and theledge portion 4. Each of the terminal strips 64 and its insulating strip66 is secured in .place by means of a fastening screw 68, which extendsthrough the ledge portion 4 and an opening in the insulating strip 66,to be threadedly engaged in a threaded opening provided in each terminalstrip 64. It will be noted that each of the insulating strips 66, whichmay be of any desired insulating material such, for example, as ber orthe like,'projects inwardly beyond the inner end of its associatedterminal strip 64, for a purpose to be described. Each of the terminalstrips 64 is provided at its outer end with a terminal screw 70 for thepurpose of securing an electrical conductor thereto. Each of theterminal strips 64 is also provided with an adjustingscrew 72 whichpasses through each terminal strip 64 and its associated insulatingstrip 66 and is threadedly engaged in a threaded opening provided in theledge portion 4 of the base. The central portion of the upper surface ofthe ledge portion 4 of the base is recessed, as indicated at 73,' topermit adjustment of the inner end of each termina-l strip and itsassociated insulating strip 66 toward and away from the ledgeportion 4of the base. Preferably the'terminal strips 64 should be of a goodelectrical conducting material which has some resilience, so that theinner end thereof can be moved toward the ledge portion 4 bytheadjusting screw 72, and upon backing` out of the screw it will return toits original position.v By the same token, the insulating strips 66should be of a material having some exibility, so that the inner endsthereof will be able to` follow the abovementionedmovement of theterminal strips 64.

Considering rst the expansible wire 60, it has one end 74 secured to theterminal 64 remote from plate portion 2 at the right-handside of therelay as viewed in Fig. l, for example, by welding, soldering or thelike. The wire then extends beneath the inner end of thecorrespondinginsulating plate 66 and then upwardly through an openingtherein and around an upper projection 76 formed on the upper end of theoperating plate 42, and thereafter it 'is reversely bent downwardlythrough another opening yin the same insulating plate 66, and thenupwardly through another opening in this insulating plate 66 to extendaround another projection 78 at the upper end of the operating plate 42to return once more through an' opening in the same insulating plate 66.From this point the wire 6G extends across the space between the twoterminals 64 at theV right side of the relay, as viewed in Fig. l, tothe innermost terminal 64 where it extends through an opening in theinsulating plate 66 of that tcrminal and then up and around anotherprojection 86 at the top of the operating plate 42 from whence it passesdown through a second opening in the same insulating plate 66 and theother end S2 of the wire is then brought up and secured to this innerterminal 64. The expansible wire 62 is similarly secured in place andextends in several courses between the terminals 64 at the left-handside of the relay, as viewed in Fig. l, and the upper end of theoperating plate 42. Thus, one end 84 of the wire 62 is secured to theterminal 64 more remote from the plate portion 2 of the base at the.left-hand side of the relay (Fig. l), andv then eX- tends upwardlythrough theinsulatingplate 66 of that terminal t0 be looped around aprojeCtAOL' Sis al the top of the operating plate 42, from whence itreturns to extend down through another opening of the insulating plate66 for this same terminal, and from there extends across the spacebetween this terminal and the terminal closest to the plate portion 2 atthe left-hand side of the relay (Fig. l), where it extends upwardlythrough a rst opening of the insulating plate 66 of this terminal to belooped around another projection 88 at the top of the insulating plate42 and back down through another opening and up through a third openingin the inner end of this same insulating plate 66 to be looped aroundstill another projection 90 at the top of the operating plate 42, andfrom there it extends back through an opening in the same insulatingplate 66, and the other end 92 of the wire is then brought up to besecured to the innermost terminal 64 at the yleft side of the relay(Fig. 1).

The expansible Wires 60 and 62 may be either mounted in place inthemanner described above with the compression spring 54 stressed, or withthe adjusting screw 58 backed out so that no stress will be exerted onthe compression spring 54, but in either case the wires should bemounted so that the lengths thereof at each side of the operating plateare substantially equal so that when the compression spring 54 isstressed, for example, byturning in the adjusting screw 58, the wires 60and 62 will maintain the operating plate 42 at a substantially centralvertically extending position as shown in Fig. l of the drawings. Thisshould be the position of the operating plate when both wires 60 and 62are at the same temperature. This can be easily adjusted when the wiresare cold and not subjected to an electric current which would heat them,by the adjusting screws 72, until the operating `plate 42 issubstantially at a vertical position, as mentioned above. It will benoted that the operating plate 42 is not at its normal central positionas shown in Fig. l, but that it is inclined somewhat to the right, whichis the position it will assume when the wire 62 is supplied withelectric current suficient to heat and expand the same. It will furtherbe noted, that at this position of the operating plate 42 the contactsare closed, the actuating spring 34 having been moved overcenter in acounterclockwise direction, and it has overtaken the operatingprojection 43 so that the left-hand side of the opening 44 in theactuating spring 34 is in engagement with the left-hand side of theoperating projection 43. Starting at this position, if the wire 62 isdeenergized and permitted to cool, the operating plate 42 will returnsubstantially to its normal vertical position, but due to the fact thatthe opening 44 in the spring 34 is of a considerably greater extent thanthe thickness of the operating projection 43 it will not move theactuating spring 34 clockwise a sufficient distance to move itovercenter. Movement overcenter will not occur until the wire 60 isenergized and heated sufficiently to expand an amount that will causethe compression spring 54 to move the upper end of the operating plate42 to the left a further amount beyond its normal central position,whereupon the overcenter movement of the actuating spring 34 will occuras previously described, and thus cause the movable contact y32 toassume its open circuit position with a snap action, all as previouslydescribed. As soon as the actuating spring 34 moves overcenter, its lineof force will not only cause opening of the contacts, but also tends tocause further movement of the actuating spring clockwise until itovertakes the operating projection 43, with the right-hand side of theclearance opening 44 in the spring engaging the right-hand side of theoperating projection 43. Again, if wire 60 is then deenergized andpermitted to cool, the operating plate 42 will assume its centralvertical position, but again, this will not move the actuating spring 34overcenter due to the lost motion connection of the operating projection43 and the actuating spring 34. Heating of wire 62 will permit theoperating plate to move to the right and move actuating spring 34overcenter counterclockwise back to the position shown in Fig. l. Itwill be noted that movement of the operatingplate 42 is caused by thecompression spring 54 when one of the wires 60 or 62 is heated andelongates. In order to effect movement of the operating plate 42, thecompression spring exerts a force longitudinally of the operating plate,and actual movement `occurs due to the angle of incidence of the wirewhich is not elongated. Inasmuch as the diameter of the expansible wiresis kept quite small the motion in response to heating of the wire isquite rapid, and for the same reason the cooling rateof the Wires isalso quite rapid, which tends to rapidly reset the operating plate 42 atits normal central location. Since movement of the operating plate 42 isdue-to a difference in length between the expansible wires 60 and 62, itmay be operated in opposite directions quite rapidly, because in movingin opposite directions the differential will be maintained as one wirewill always be heating up while the other is cooling, so that the actualrate of movement remains relatively constant, Furthermore, since thewires 60 and 62 are on opposite sides of the operating plate 42 and ofsubstantially the same length, ambient temperature has no effect on thenormal central position of the operating plate 42.

The modification of the invention illustrated in Fig. 5 of the drawingspertains to a variation in the manner of supporting the operating plate42, which comprises a plunger 94 sildably mounted in the opening 56through ledge portion 4 of the base. The plunger 94 has a socket 96formed in the upper end thereof for receiving the projection 48 in thenotch 46 in the lower edge of the operating plate 42, with considerableclearance. The plunger 94 is biased upwardly by a leaf spring 98 whichhas one end bearing against the lower end of the plunger 94, and has itsother end offset therefrom and secured to the ledge portion 4 of thebase, as by a rivet 100.

The operation of the particular support for the operating plate 42illustrated in Fig. 5 results in substantially the same relay operationas the mode of support illustrated in Figs. 1 and 2, the onlysubstantial difference being that no means of adjustment of the springpressure is provided in the form of support shown in Fig. 5, whereas thecompression spring 54 in the form of support shown in Fig. 1 can beadjusted by means of the adjusting screw 58.

Referring to Fig. 6 of the drawings, there is illustrated a portion ofan electrical outlet box 102 having an opening 104 in one wall thereof,which may be formed as the result of removing a standard type ofknockout plug normally provided in this type of box. These knockoutopenings 104 are generally circular in form. The relay illustrated inFig. 6 is provided with a separate base 106 on which the terminal 64,operating plate 42 and wires 60 and 62 are mounted. This supporting base106 is generally circular in form, and should be of an insulatingmaterial, such, for example, as fiber or a molded insulating material.The base 106 is adapted to be mounted in one end of a generallycylindrically shaped housing part 108, which extends for substantiallythe entire length of the actuating plate 42 and may be made of metal,preferably a metal having some resiliency, such as sheet steel. The base106 is secured in the left-hand end of the cylindrical housing part 108,as viewed in Fig. 6, in any desired manner, being located by la flangeon the base engaging the flanged end 110 of the cylindrical housing part108. This permits the outer side of the base 106 to project through thereduced opening lformed by the flange end 110 to permit attachment ofconductors in a control circuit to terminal screws associated with eachof the terminals 64. The cylindrical housing part 108 preferably haslongitudinally extending detent ribs 111 formed thereon which may bespaced about the housing part 108 and terminate short of the inner endof the cylindrical housing part 108 where an outwardly extending ange112 is formed.

The relay contacts in this embodiment of the invention are mountedwithin a laterally enlarged casing part 114 of insulating material, suchas amolded insulating material, and this casing part is assembled to thepart 108 in any desired way, for example, as by screws 116 which extendthrough the flange 112 of the cylindrical casing part 108 to bethreadedly engaged in openings provided in the casing part 114. Thecasing part 114 is provided with suitable openings for conductors 118which connect vto the electrical outlet which may be mounted in the box102.

The reason for the particular Way of supporting the relay and theparticular casing therefor illustrated in Fig. 6 is to facilitatemounting the assembly in a knockout opening 104 of an outlet box 102. Itis believed apparent that such assembly can readily take place by merelyinserting the cylindrical housing part 108 into the knockout opening 104from the interior of the outlet box 102, until the inner wall of the boxengages the flangev112 on the housing part 108, at which time the detentribs 111, which engage the edge portions of the knockout hole 104 duringinsertion ofthe housing part 108, will slip past these edge portions ofthe knockout opening and engage over outer edge portions of the knockoutopening edge portions, to. securely yet releasably fasten therelay inplace in the lknockout opening 104. If it is desired to replace a relaymounted in this manner, it can be readily done by simply withdrawing thecylindrical housing part 108 inwardly from the knockout opening 84, anda new relay mounted in the opening in the same manner described above.

As mentionedat the outset, one application of a relay constructedinaccordance with this invention is in the low voltage control ofresidential wiring, where these relays maybe mounted in residence outletboxes in the manner shown in Fig. 6, and described above. In this typeof application the relay is connected in circuit'sub stantially as shownin Fig. 7, where the power supply conductors are connected to theprimary winding 124 of a transformer having a low voltage secondarywinding 126. One illustrative example would be Where the primary voltageis about 115 volts, and the secondary voltage is about volts. One end ofthe secondary winding 126 may be connected by a conductor 12S to one endof each of the expansible wires 60 and 62 by'rneans of their respectiveconductors 120. The other side of the low voltage secondary winding 126may be connected by a conductor 130 to the movable contacts 132 ofsingle pole double throw control switches, each having a pair ofstationary contacts 134 and 136. One of the supply conductors isconnected to one of the conductors 11S leading to one of the relaycontacts 20, while the other supply conductor 122 is connected by meansof a conductor 138 to the load and this, in turn, is connected by meansof the other conductor 118 to the other contact 12 of the relay.

It is apparent that any desired number of control switches havingmovable contacts 132 may be provided, with each contact 134 thereofbeing connected to the conductor 120 leading to the other end of one ofthe expansible wires 60, and the other contact 136 of each controlswitch being connected to the other end of the other expansible wire 62by means of a conductor 120.

As stated above, this permits any desired number of low l snap action,and provides stability in each of these positions. Moreover, thecontacts are under the control of an actuator spring 34 which is movedin a generally pivotal manner to cause the above-mentioned snap actionmovement. Finally, the spring actuator for the contacts is actuallymoved by an operating plate 42 and its biasing spring under the controlof expansible wires 60 and 62. While the movement due to expansion ofsuch wires is relatively small, the particular arrangement permitssufficient movement of the Contact operating spring 34 as to cause thesnap action movement of the relay contacts previously referred to. Thesize of the expansible wires 60 and 62 is kept small to maintain a rapidheating and cooling rate and the arrangement is such that movement isdue to the differential expansion of the two expansible wires 60 and 62,so that a rapid back and forth open and closed operation of the relaycan occur.

Having particularly described preferred embodiments of this invention asrequired by the patent statutes, it is desired that the invention be notlimited to these particular structures as it will be apparent to personsskilled in the art that many modifications and variations thereof may bemade without departing from the broad spirit and scope of thisinvention. Thus, variations in the supporting base structure have beenillustrated herein, as well as supporting structure both`with andwithout an enclosing casing. Likewise, it is apparent that relaysconstructed in accordance with this invention may be employed for manyuses other than the particular one which has been referred to, namelythe low voltage control of residential electrical outlets. Thus, theinvention should be interpreted as broadly as consistent With the priorI claim as my invention:

l. A relay comprising, a base of insulating material, separable contactsmounted on said base, an elongated contact operating member having oneend supported on said base for longitudinal and pivotal movement, meansengaging the other end of said operating member for operating saidcontacts in response to lateral movement of said other end ofthe'operating member, thermally expansible wires connecting said otherend of the operating member to said base at opposite sides of saidoperating member, respectively, and spring means reacting between saidbase and said operating member to bias said member longitudinally towardits aforesaid other end to place said wires under tension when cool sothat when one wire is heated said other end of the operating member ismoved toward the opposite side by the tension in the other wire tooperate said contacts to one position and said operating member is movedin the opposite direction when the other wire is heated to move saidcontacts to another position.

2. A relay comprising, a base of insulating material, separatblecontacts mounted on said base, an elongated contact operating memberhaving one end pivotally mounted on a support which is slidablysupported on said base for movement in a direction longitudinally ofsaid operating member, means engaging the other end of said operatingmember for operating said contacts in response to lateral movement ofsaid other end of the operating member, thermally expansible wiresconnecting said other end of the operating member to said base atopposite sides of said operating member, respectively, and spring meansreacting between said 4base and said support for biasing said support ina direction longitudinally of said operating member toward its aforesaidother end to place said wires under tension so that when one wire isheated said other end of the operatingmember is moved toward theopposite side by said spring means to operate said contacts to oneposition, and said operating member is moved in the opposite directionwhen the other wire is heated to move said contacts to another position.

3. A relay comprising, a base of insulating material, separable contactsmounted on said base, an elongated contact operating member having oneend mounted on said base for both longitudinal movement away from saidbase and pivotal movement, means engaging the other end of saidoperating member for operating said contacts in response to pivotalmovement of said operating member about an axis adjacent said base,thermally expansible wires connecting said other end of the operatingmember to said base at opposite sides of said operating member,respectively, spring means reacting between said base and said supportfor biasing said operating member longitudinally toward the aforesaidother end of said operating member to place said wires under tension sothat when one wire is heated said other end of the operating member ismoved toward the opposite side by the tension in the other wire and saidspring means to operate said contacts to one position, and saidoperating member is moved in the opposite direction when the other wireis heated to move said contacts to another position, and manuallyadjustable means engaging said spring means for selectively varying theforce exerted thereby.

4. A relay comprising, a base of insulating material, separable contactsmounted on said base, an elongated contact operating member having oneend loosely received in a recess formed in said base, means engaging theother end of said operating member for operating said contacts inresponse to pivotal movement of said operating member about an axisadjacent said base, thermally expansible wires connecting said other endof the operating member to said base at opposite sides of said operatingmember, respectively, and spring means reacting between said base andsaid operating member for biasing said operating member longitudinallyoutwardly of said recess to place said wires under tension so that whenone wire is heated said other end of the operating member is movedtoward the opposite side by the tension in the other wire and saidspring means to operate said contacts to one position, and saidoperating member is moved in the opposite direction when the other wireis heated to move said contacts to another position, and means foradjusting the force exerted by said spring means,

5. A relay comprising, a base of insulating material, separable contactsmounted on said base, means including a member movable overcenter formoving one of said contacts with a snap action to and from stablepositions where said contacts are open and closed, respectively, anelongated contact operating member having one end movably mounted onsaid base, a lost motion connection between the other end of saidoperating member and said contact moving means for operating saidcontacts in response to pivotal movement of said operating member aboutan axis adjacent said base and permitting said overcenter member to movebeyond the portion to which it is moved by said operating member,thermally expansible wires connecting said other end of the operatingmember to said base at opposite sides of said operating member,respectively, and said wires being under tension when cool so that whenone wire is heated said other end of the operating member is movedtoward the opposite side by the tension in the other wire to operatesaid contacts to one position, and said operating member is moved in theopposite direction when the other wire is heated to move said contactsto another position.

6. A relay comprising, a base of insulating material, separable contactsmounted on said base, an elongated contact operating member having oneend movably mounted on said base, means engaging the other end of saidoperating member for operating said contacts in response to pivotalmovement of said operating member about an axis adjacent said base,thermally expansible wires connecting said other end of the operatingmember to said base at opposite sides of said operating member,respectively, said wires being under tension when cool so that when onewire is heated said other end of the operating member is moved towardthe opposite side by the tension in the other wire to operate saidcontacts to one position, and said operating member is moved in theopposite direction when the other wire is heated to move said contactsto another position, and each of said wires comprising a continuouslength of wire wound in multiple loop-s between the base and said' otherend of the operating member.

7. A relay comprising, a base of insulating materiaL separable contacts,one of which is mounted at a xed position on said base and the other ofwhich is mounted on one end of a resilient member having its other endmounted on said base, said resilient member having an intermediate,substantially H-shaped cutout portion to provide opposed integral armsextending inwardly from each end, an actuating member having opposedoutwardly biased arms pivotally engaging the inner free ends of saidintegral arms so that generally pivotal movement of said actuatingmember in opposite directions will cause movement of said integral armsin opposite directions to result in snap movement of a contact mountedon said resilient member to and from two stable positions where saidcontacts are open and closed, respectively, an elongated operatingmember having one end movably mounted on said base and its other endengaging said actuating member for operating said contacts in responseto pivotal movement of said operating member about an axis adjacent saidbase, thermally expansible wires connecting said other end of theoperating member to said base at opposite sides of said operatingmember, respectively, and said wires being under tension when cool sothat when one wire is heated said other end of the operating member ismoved toward the opposite side by the tension in the other wire tooperate said contacts to one position, and said operating member ismoved in the opposite direction when the other wire is heated to movesaid contacts to another position.

8. A relay comprising, a base of insulating material, separablecontacts, one of which is mounted at a fixed position on said base andthe other of which is mounted on one end of a flexible member having itsother end mounted on said base, said flexible member having compressionmembers extending inwardly from each end with at least the inner ends ofsaid compression members being movable relative to each other, anactuating member having opposed outwardly biased arms pivotally engagingthe inner free ends of said compression members, so that generallypivotal movement of said actuating member in opposite directions willcause movement of said compression members in opposite directions toresult in snap movement of a Contact mounted on said resilient member toand from two stable positions where said contacts are open and closed,respectively, an elongated operating member having one end movablymounted on said base and its other end engaging said actuating memberforoperating said contacts in response to pivotal movement of saidoperating member about an axis adjacent said base, thermally expansiblewires connecting said other end of the operating member to said base atopposite sides of said operating member, respectively, and said wiresbeing under tension when cool so that when one wire is heated said otherend of the operating member is moved toward the opposite side by thetension in the other wire to operate said contacts to one position, andsaid operating member is moved in the opposite direction when the otherwire is heated to move said contacts to another position.

9. A relay comprising, a base of insulating material, separablecontacts, one of which is mounted at a fixed position on said base andthe other of which is mounted on one end of a flexible member having itsother end mounted on said base, said exible member having spaced opposedportions associated with the aforesaid ends of said ilexible member,respectively, so that at least the spaced opposed edges of said portionsare movable relative to each other, an actuating member having opposedoutwardly biased arms pivotally engaging said opposed 11 l edges of saidportions, so that generally pivotal Vmovement of said actuating memberin opposite-directions'willcause movement of said opposed portions inopposite directions to result in snap movement of a contact mounted onsaid resilient member to and from two stable positions where saidcontacts are open and closed, respectively, an elongated operatingmember having one end movably mounted on s aid base and its other endengaging said actuating member for operating said contacts in responseto pivotal movement of said operating member about an axis adjacent saidbase, thermally expansible wires connecting said other end of theoperating member to said base at opposite sides of said operatingmember, respectively, and said wires being under tension when cool sothat when one wire is heated said other end of the operating member ismoved toward the opposite side by the tension in the other wire tooperate said contacts to one position, and said operating member ismoved in the opposite direction when the other wire is heated to movesaid contacts to another position.

10. A relay comprising, a base of insulating material, separablecontacts, one of which is mounted at a xed position on said base and theother of which is mounted on one end of a llexible member having itsotherend mounted on said base, said flexible member havinglongitudinally spaced opposed portions associated with the opposite endsof said exible member, respectively, and the spaced opposed edges ofsaid portions being movable in opposite directions relative to eachother, an actuating member having opposed outwardly biased armspivotally engaging said opposed edges of said portions so that generallypivotal movement of said actuaing member in opposite directions willcause the aforesaid movement of said opposed portions to result in snapmovement of the contact mounted on said flexible member to and from twostable positions where said contacts are open `and closed, respectively,and pivotally mounted electroresponsive means directly engaging saidactuating member to cause generally pivotal movement thereof in oppositedirections.

ll. A relay comprising, a base of insulating material, separablecontacts, one of which is mounted at a fixed position on said base andthe other of which is mounted on one end of a flexible member having itsother end mounted on said base, said ilexible member havinglongitudinally spaced opposed portions associated with the opposite endsof said ilexible member, respectively, and spaced opposed edges of saidportions being movable in opposite directions relative to each other, anactuating member having opposed outwardly biased arms pivotally engagingsaid opposed edges of said portions, so that generally pivotal movementof said actuating member in opposite directions will cause the aforesaidmovement of said opposed portions to result in snap movement of theContact mounted on said llexible member to and from two stable positionswhere said contacts are4 open and closed, respectively, and pivotallymounted electroresponsive means having a direct lost lmotion connectionexible member to and fr m tworstable positions where said contacts areopen and closed, respectively, and pivotally mounted electroresponsivemeans directly engaging said actuating member to cause generally pivotalmove ment thereof in opposite directions.

13. A relay comprising, a base of insulating materiaL separablecontacts, one of which is mounted at a tixed position on said base andthe other of which is mounted on one end of a llexible member having itsother end mounted on said base, said liexible member having spacedopposed portions associated with the opposite ends of said flexiblemember, respectively, so that at least the spaced opposed edges of saidportions are movable relative to each other, an actuating member havingopposed outwardly biased arms pivotally engaging said opposed edges ofsaid portions, so that generally pivotal movement of said actuatingmember in opposite directions will cause movement of said opposedportions. in opposite directions to result in snap movement of thecontact mounted on said flexible member to and from two stable positionswhere said contacts are open and closed, respectively, an elongatedoperating member extending from said actuating member substantiallytransversely of said flexible member to have its remote end movablymounted on said base and its other end engaging said actuating memberfor operating said contacts in response to pivotal movement of saidoperatingl member about an axis adjacent said base, thermally expansiblewires connecting said other end of the operating member to said base atopposite sides of said operating member, respectively, and said wiresbeing under tension when cool so that when one wire is heated said otherend of the operating member is moved toward the opposite side by thetension in the other wire to operate said contacts to one position, andsaid operating member is moved in the opposite direction when the otherwire is heated to move said contacts to another position.

14. A relay comprising, a base of insulating material, separablecontacts, one of which is mounted at a xed position on said base and theother of which is mounted on one end of a flexible member having itsother end mounted on said base, said flexible member having spacedopposed portions associated with the opposite ends of said ilexiblemember, respectively, so that at least the spaced opposed edges of saidportions are movable relative to each other, an actuating member havingopposed outwardly biased arms pivotally engaging said opposed edges ofsaid portions, so that generally pivotal movement of said actuatingmember in opposite directions with said actuating member to causegenerally pivotal opposed outwardly biased arms pivotally engaging theinner free ends of said integral arms, said integral arms being movablein opposite directions relative to one another lso that generallypivotal movement of said actuating member in opposite directions willcause movement of said integral arms in the aforesaid manner to resultin snap movement of the contact mounted on said will cause movement ofsaid opposed portions in opposite directions to result in snap movementof a contact mounted on said flexible member to and from two stablepositions where said contacts are open and closed, respectively, anelongated operating member extending from said actuating membersubstantially transversely of said flexible member to have its remoteend movably mounted on said base and its other end engaging saidactuating member for operating said contacts in response to pivotalmovement of said operating member about an axisadjacent said base,thermally expansible wires connecting said other end of the operating,member to said base at opposite sides of said operating member,respectively, and said Wires being under tension when cool so that whenone wire is heated said other end of the operating member is movedtoward the opposite side by the tension in the other wire to operatesaid contacts to one position, and said operating member is moved in theopposite direction when the other Wire is heated to move said contactsto another position, a casing for said relay comprising a generallycylindrical part enclosing said operating member and expansible wires,and a transverse casing part at one end of said cylindrical partenclosing said contacts, and said cylindrical casing part having adetent portion formed thereon adjacent said transverse casing part forcooperation with the edge of a circular 13 mounting opening of a size tojust receive said cylindrical casing part to secure the relay in such anopening.

15. A relay comprising, a base of insulating material, separablecontacts, one of which is mounted at a xed position on said base and theother of which is mounted on one end of a exible member having its otherend mounted on said base, said llexible member having a pair oflongitudinally spaced opposed portions associated with the opposite endsof said ilexible member, respectively, and the spaced opposed edges ofsaid portions being movable in opposite directions relative to eachother, an actuating member having opposed outwardly biased armspivotally engaging said opposed edges of said portions, so thatgenerally pivotal movement of said actuating member in oppositedirections will cause the aforesaid movement of said opposed portions toresult in snap movement of a contact mounted on said resilient member toand from two stable positions where said contacts are open and closed,respectively, and operating means pivotally and movably mounted on saidbase and directly engaging said actuating member for operating saidactuating member to cause generally pivotal movement of the latter inopposite directions.

References Cited in the le of this patent UNITED STATES PATENTS1,773,708 Whittingham Aug. 19, 1930 1,868,500 Hanel July 26, 19322,076,275 Jorgenson Apr. 6, 1937 2,256,499 Schmidinger Sept. 23, 19412,308,522 Leuthold Jan. 19, 1943 2,340,877 Hausler Feb. 8, 19442,387,089 Peterson et al Oct. 16, 1945 2,429,074 Rugh Oct. 14, 19472,547,999 Brockway Apr. 10, 1951 2,558,219 Kohl June 26, 1951 2,595,967McCloy May 6, 1952 2,689,283 Pulvari Sept. 14 1954 2,747,052 Blume May22, 1956 2,811,603 Koch et al. Oct. 29, 1957

